1. Field of the Invention
The present invention relates to a device and a method used in a wireless communication system, and more particularly, to a device and a method of aggregating a wireless local area network (WLAN) and a long term evolution (LTE) system.
2. Description of the Prior Art
A long-term evolution (LTE) system provides high data rate, low latency, packet optimization, and improved system capacity and coverage. In the LTE system, a radio access network known as an evolved universal terrestrial radio access network (E-UTRAN) includes at least one evolved Node-B (eNB) for communicating with at least one user equipment (UE), and for communicating with a core network including a mobility management entity (MME), a serving gateway, etc., for Non-Access Stratum (NAS) control.
A LTE-advanced (LTE-A) system is an evolution of the LTE system. The LTE-A system extends cell coverage of an eNB, increases peak data rate and throughput, and includes advanced techniques, such as carrier aggregation (CA), licensed-assisted access (LAA) using LTE, etc.
The LTE system may be aggregated with a wireless local area network (WLAN) to improve throughput of the LTE system. That is, the eNB transmits/receives data via both LTE communication and WLAN communication to/from the UE.
In one example, the UE may disconnect a WLAN configured by the eNB, while the eNB does not know that the UE has disconnected the WLAN. The eNB keeps transmitting LTE packets to the UE via the WLAN, and resources for transmitting the LTE packets are wasted. In another example, the UE has connected to a WLAN according to a user's selection or a selection algorithm. After a while, the UE may receive a message configuring the UE to connect to another WLAN. It is unknown how the UE should operate when this conflict occurs.
Thus, how to aggregating the WLAN and the LTE system when the above problem occurs is an important problem to be solved.